1. Field of the Invention
The present invention relates to electronic apparatuses, such as laptop personal computers, word processors, etc., card-type electronic components used with the electronic apparatuses, for the delivery of signals, e.g., data transmission, therewith, and electronic systems having an expanding apparatus for expanding the functions of the electronic apparatuses.
2. Description of the Related Art
Some of laptop personal computers can incorporate card-type electronic components, such as memory cards, modem cards, etc., which are adapted to be laterally inserted into the computer body, in order to expand their functions.
Generally, in the computers of this type, a card inlet slot is formed in a side face of the body, and a card storing section is formed in the body so as to communicate with the inlet slot. A card can be incorporated into the computer body by being inserted into the card storing section through the inlet slot.
The card must be taken out of the computer body when its use is finished or when it is to be replaced with another one. Cards are so thin, however, that they are not very easy to handle. Conventionally, therefore, computers use ejector mechanisms of the following three types.
Type 1: The size of the card storing section is adjusted so that incorporating the card is finished when the card is inserted to about half its length into the storing section. When the incorporation is finished, therefore, the rear portion of the card projects long outside the computer body. Thus, a user can remove the card by taking it out of the card storing section with the exposed or projecting portion of the card between his fingers.
Type 2: The card storing section formed in the computer body has a size large enough to receive the whole card. The storing section is arranged close and parallel to a side face of the computer body which extends at right angles to the body side face in which the card inlet slot is formed. Formed on this side face is a knob which is slidable in the loading direction of the card. The knob is connected with a card push-out mechanism in the card storing section. When the push-out mechanism is actuated in association with the sliding motion of the knob, the card in the storing section is pushed out of the body through the card inlet slot.
Type 3: The card storing section formed in the computer body has a size large enough to receive the whole card. Two recesses are formed individually at the opposite side face portions of the body which are adjacent to the opposite end sides of the card inlet slot of the card storing section. These recesses can receive the user's finger tips which are to hold and draw out an end portion of the card long from the storing section. Thus, the user can take out the card from the card storing section to the outside of the computer body by inserting his finger tips into the recesses, holding that portion of the card at the end portions of the inlet slot between the finger tips, and then drawing out the card from the body.
According to the card ejector mechanism of the first type described above, part of the loaded card projects long from the computer body, constituting a hindrance to the transfer of the computer. A laptop computer, which is a portable computer, may be carried with the card therein. In doing this, however, the projecting card is liable to interfere with some other parts, thus hindering the transfer of the computer.
In the card ejector mechanism of the second type, the card, which is housed in the computer body, is not a hindrance to the conveyance of the computer. Since the card is pushed out of the computer body by sliding the knob, however, the knob and the card storing section should be located adjacent to each other. According to this arrangement, therefore, the space for the incorporation of the card is inevitably restricted to the regions on either side of the computer body.
In the card ejector mechanism of the third type, as in the case of the second-type ejector mechanism, the card is not a hindrance to the conveyance of the computer. Since the recesses formed on the opposite end sides of the card inlet slot are large, however, the regions adjacent to the slot are occupied by the recesses. In the case of a laptop personal computer in which a dead space in its body is utilized for the incorporation of the card, therefore, the computer body must inevitably be increased in size.
With the progress of semiconductor technology, various card-type electronic components which are in conformity to the standards provided by, e.g., JEIDA (Japanese Electric Industry Development Association) have recently been developed and spread. The card-type electronic components include various cards, such as modem cards, which handle high-frequency signals. These components must be fully shielded. In conventional card-type electronic components, which are represented by memory cards, for example, grounding terminals are arranged only in an interface connector to be connected to the computer body. In this case, the ground contact area cannot be wide enough for satisfactorily antijamming.
Accordingly, it has been proposed that one such card-type electronic component should be designed so that flat shielding plates are arranged individually on the upper and lower surfaces of a card body, and are connected electrically to grounding contact pieces on the computer body to be loaded with the electronic component. When the electronic component is loaded into a card storing section of the computer body, the shielding plates are brought individually into direct contact with the grounding contact pieces, which are arranged above and below in the card storing section.
However, the above-described arrangement involves the following problems.
In the standardized card-type electronic components, the thickness of the card body is prescribed only with respect to its maximum value (e.g., 5.0 mm in the case of the standards Type II provided by JEIDA), so that it varies depending on the types of components, manufacturers, etc. In some of various kinds of cards, those portions which are to be in contact with the grounding contact pieces in the card holding section of the computer body are extremely different in thickness. In alternatively loading these various cards into the same card storing section, in particular, the following problems arise.
If a relatively thin card is used after prolonged use of a thicker card of which the thickness of the portions to be in contact with the grounding contact pieces in the card holding section is substantially equal to the prescribed maximum dimension, or if thick and thin cards are repeatedly used by turns, the grounding contact pieces fail to enjoy satisfactory contact with the shielding plates of the card, thus bringing about a non-contact or unstable contact state, due to reduction of the spring pressure of the grounding contact pieces. In such a case, the shielding effect of the card is ruined completely, or noises are liable to be produced due to unstable contact.
In loading into or unloading the card-type component from the card storing section, in the arrangement described above, moreover, the grounding contact pieces in the holding section slide individually on the upper and lower shielding plates of the card. As the contact pieces slide in this manner, the shielding plates and/or the contact pieces are shaven away to produce metallic powder. This metallic powder may possibly enter the computer body and cause the computer to operate improperly. In general, moreover, the upper and lower shielding plates of the card-type component are each in the form of a design plate bearing a coating, patterns, etc. for improved design properties, except for those conduction portions thereof which are brought into contact with the grounding contact pieces when the component is set in a predetermined position in the card storing section. When the card-type component is loaded into or unloaded from the card storing section, as mentioned before, design portions of the shielding plates are also brought into sliding contact with the grounding contact piece, so that removal of the coating or the like is caused. Since neither coating nor patterns are put on the conduction portions, moreover, the design properties of the card-type component may possibly be lowered.
Recently, there has been a demand for additional reduction in size of the computers of this type, for improved portability and handleability. To cope with this, each part of the housing of the computer is formed having a very thin wall. In this case, however, the strength of each part of the housing is so low that the housing wall may be deformed or distorted when it is subjected to an external force. In such a situation, the housing wall may possibly interfere with components in the housing, thereby damaging them. Display units of some computers contain an elongated fluorescent lamp with a relatively small diameter. If the wall portion of these units is deformed or distorted, however, there is a fear of the lamp being damaged.
Usually, moreover, one such computer comprises a keyboard. The dimensions of the keyboard constitute a primary factor essential to the reduction of the computer size. The keyboard comprises a rectangular printed board and a number of keys arranged lengthwise and crosswise on the printed board. Each key is in the form of a truncated pyramid. More specifically, each key has a rectangular top face, a rectangular bottom face wider than the top face, and four slanting side faces extending individually from the four side edges of the top face to their corresponding side edges of the bottom face so as to spread out downward. These keys are arranged at predetermined intervals, and constitute a key array having a rectangular outline as a whole.
The size (lengthwise and crosswise dimensions) of the key array, which determines the size of the keyboard, depends on the number of keys, the size of the key top face, and the intervals between the keys. If the ease of operation of the keyboard is taken into consideration, however, the minimum values of these dimensions are determined as a necessity, so that it is difficult to reduce the number of keys, top face size, and key intervals. Therefore, the keyboard dimensions cannot be made smaller than fixed values. Partly because of this, the size of the whole computer can be reduced only limitedly.
The personal computer of this type comprises a body, including upper and lower cases, and a display unit swingably mounted on the upper case. Usually, a driver circuit, control circuit, memory unit, etc. of the computer are arranged in the lower case of the body. In assembling these components, the upper case, fitted with the display unit, is joined to the lower case which is mounted with the driver circuit and other elements. In doing this, a signal cable led out of the display unit is connected to a connector of the control circuit mounted in the lower case.
In order to facilitate the connection of the signal cable of the display unit to the lower case, in joining the upper and lower cases together in this manner, the signal cable should be formed having some extra length. However, such an extra length portion of the cable is a hindrance to the internal arrangement of the computer body, and leading it about is a troublesome task. Therefore, an extra space for this extra length portion must be secured in the body. This entails difficult assembling operation and constitutes a hindrance to the miniaturization of the computer.
Electronic parts arranged in the computer body include high-performance integrated circuits, such as a CPU, VGA (variable gain amplifier) driver, etc., which act as superheating elements. In some cases, therefore, those wall portions of the body which are situated adjacent to these superheating electronic parts may be heated to a temperature of about 50.degree. C. In general, the human body feels hot when exposed to a temperature of 40.degree. C. or more. Accordingly, the personal computer is designed so that the superheating parts are arranged adjacent to the bottom wall of its body which normally is not accessible to the user's hands. In the case of a portable computer, however, the user should touch its bottom wall as he carries it about, and may harbor suspicion, feeling hot.
Heat from the superheating electronic parts may be screened by arranging a shielding plate between the parts and the body wall portions. In this case, however, the whole computer is inevitably large-sized, and its portability is low.
In general, the computer of this type enjoys a compact design which ensures higher portability and a minimized desk setting area. Therefore, the functions of the computer itself are limited. If additional functions other than standard functions are required, the computer is connected to an function expanding apparatus before use. Conventionally, the computer and the expanding apparatus are connected to each other by means of connectors for transferring data. However, the connection only by means of the connectors cannot provide a satisfactory fixing strength. The connectors may be easily disengaged due to an impact or the like produced during the operation of the computer, thus resulting in contact failure or some other trouble.
Recently, there have been provided an expanding apparatus having a mounting section on which the whole body of a computer can be mounted. Expanding apparatuses disclosed in U.S. Pat. Nos. 4,769,764 and 4,903,222, for example, comprise a housing which contains expansion means, including a hard disk drive, circuit board for storage, etc. The housing is formed having a mounting recess which corresponds to the computer in size. The computer is releasably fitted into the mounting recess from above or from the front. A plug-in connector for the connection to the expanding apparatus is disposed on the rear face of the computer. When the computer is set in the mounting recess, this connector is fitted into another plug-in connector attached to the mounting recess of the apparatus. Thus, the computer and the expanding apparatus are connected electrically to each other.
The mating force of the connectors is great enough to secure the connection between the computer and the expanding apparatus. Removing the computer from the mounting recess requires a greater force than this mating force. Accordingly, the computer cannot be easily detached from the mounting recess by hand, so that handling the system costs much labor.
The mounting recess is open to the front of the housing of the expanding apparatus, as well as to the top side. In detaching the computer, therefore, its front end portion may possibly be unexpectedly raised even though the connectors are not disengaged. In such a case, the computer is urged to rock upward around the junction between the connectors, so that the connectors are wrenched. As a result, an unreasonable force is applied to the connectors, thereby breaking them down.
Such breakdown of the connectors may be prevented by designing the connector on the mounting recess side for vertical oscillation.
According to this arrangement, however, a space for the oscillation of this oscillating connector must be secured around it, and high-frequency noises, which are produced by the expanding apparatus, leak out through this space, thereby possibly inducing communication jamming.
Further, lead wires connecting the oscillating connector and a printed board in the housing should be lengthened by a margin for the rocking motion of this connector. Accordingly, the wiring operation is troublesome, and the wire arrangement in the housing is complicated.
If the computer is displaced by an external force, with the connectors connected to each other, the connectors may possibly be damaged. Conventionally, therefore, the connector on the expanding apparatus side is arranged so as to be shiftable in the vertical and crosswise directions, that is, in the directions perpendicular to the direction of engagement between the connectors. By this arrangement, the displacement of the computer can be absorbed, so that the connectors can be prevented from being damaged. In the conventional expanding apparatus, however, the connector is immovable in the longitudinal direction or in the connector engaging direction, although it is shiftable in the vertical and crosswise directions. If the computer is subjected to a longitudinal external force while it is connected to the expanding apparatus, therefore, the connectors may possibly be disengaged from each other. In such a case, the computer behaves wrongly, so that in-process data may be destroyed, or the computer system may be damaged.